Flu season is quickly approaching and with it, many questions and concerns about its interaction and overlap with the COVID-19 pandemic.

“Even before the emergence of COVID, it could be difficult during flu season for people to know if their respiratory symptoms were caused by the flu, a cold, allergies or a sinus problem, “ says  Darci Portie, APRN, FNPC, with Iowa Primary Care. “Now with everyone worried about a spike in COVID over the winter, which is also peak flu season, people will be even more worried about the source of their respiratory symptoms.”

Portie explains that the conditions differ in their cause. “COVID is caused by the 2019 coronavirus, and the flu is caused by any of several different types and strains of influenza viruses. Different strains circulate each year.”

Both viruses cause many of the same symptoms and are transmitted via close personal contact and through respiratory droplets, making it difficult to distinguish one from the other. All respiratory illnesses share some similar symptoms that can affect the entire respiratory system – airways, lungs and blood vessels.

The symptoms that are most common in COVID-19 and the flu include:

  • Fever (of more than 100 degrees Fahrenheit)
  • Chills
  • Headache
  • Cough
  • Muscle pain and body aches
  • Weakness
  • Fatigue (extreme tiredness or lack of energy)
  • Nausea or vomiting (more common in children
  • Diarrhea (more common in children)

Portie says there are some specific differences that have been identified that will help determine if the cause of respiratory symptoms is more likely from COVID or the flu, including:

Symptom Onset

  • The flu comes on suddenly, with symptoms appearing one to four days after infection.
  • COVID-19 symptoms can be more gradual. While COVID-19 symptoms can develop as early as two days after you’re infected, the (CDC) says five days after infection is typical, and it’s possible to be infected but not show any symptoms for up to 14 days.

Cough type and severity

  • The flu usually causes a mild, dry cough
  • COVID-19 cough symptoms are more severe, usually dry, persistent and can leave you short of breath.

Unique symptoms

COVID-19 symptoms that don’t typically overlap or are less common with the flu include:

  • Shortness of breath or difficulty breathing
  • Runny or stuffy nose
  • Sore throat
  • Shaking with chills
  • New and sudden loss of taste or smell

Portie explains that a possibility of COVID is characterized by at least two of its symptoms being present, but any one common flu symptom could be an indicator of the virus.

Portie says if you develop symptoms and are unsure if you may have the COVID or the flu, contact your doctor or see a trusted healthcare provider. “Because symptoms are so similar and can vary from person to person – the only way to confirm whether it’s COVID-19 or influenza is through testing.”

She stresses that prevention for both conditions is important, especially this year when both viruses are expected to peak over the colder months. “The flu vaccine is readily available and recommended for everyone over the age of six months. There is not a vaccine available for COVID yet, so continuing to follow the preventive measure that have been in place since the virus emerged remain critical.”